Mixed metal oxides are a highly attractive and feasible option to address the stability limitations in heterogeneous catalysis. They offer distinct surface properties, like tunable defects, oxygen vacancies, enhanced redox behavior etc. when compared to bulk metal oxides. These mixed metal oxides show synergistic interactions which demonstrates significantly enhanced catalytic activity, selectivity, and thermal stability.
Ammonia decomposition reaction:
The ammonia decomposition reaction (ADR) is the most effective route for carbon-free hydrogen (green hydrogen) on-demand generation, using ammonia as a hydrogen carrier that is much easier to transport and store than molecular hydrogen. Although ruthenium-based materials are the most active catalysts for ADR, the large-scale application of the attractive ADR technology is limited by the high price and scarcity of ruthenium. Therefore, developing highly active and stable single atom Ru catalysts with low Ru loading is critical for efficient and low-cost ammonia decomposition technology. Here, we report new class of reducible layered mixed metal oxide support (MgCeAl2Ox) promoted with an alkali metal (Cs) to generate highly effective channels for hydrogen spillover to remove hydrogen species, generated via ammonia decomposition, from catalytically active sites, increasing turnover frequency. The defects created (due to grain boundaries between oxides) on the support also enhance the Ru dispersion (~67%). The Cs-MgCeAl2Ox support significantly enhances catalyst basicity, promotes N2 desorption, and improves the turnover frequency for NH3 decomposition. Ammonia conversions of 99% and 90% were achieved at space velocities of 15,000 and 20,000 mL gcat-1 h-1, respectively, at 400 oC and 1.0 bar. Furthermore, ~90% conversion was achieved at a higher space velocity of 40,000 mL gcat-1 h-1 and an economically feasible temperature of 450 oC. Moreover, the catalyst was shown to be stable at 450 oC for 320 hours, capable of maintaining complete ammonia conversion to hydrogen.
Additionally, a different support material with high surface area is synthesized with enhanced dispersion of Ru. More than 85% conversion was achieved at 400 oC with 40,000 mL gcat-1 h-1. Also, Ru-free catalyst (Co-based) are synthesized. Preliminary catalyst tests had shown promising results.
Water gas-shift reaction:
Efficiency of the current fossil fuel-based syngas plants for hydrogen and ammonia production could be significantly enhanced by developing a highly active catalyst for water gas shift reaction. Considering the advanced CO2 and hydrogen separation downstream the shift reactors, would significantly reduce the overall production cost of syngas-based plants. Thus, engineering dual-functional catalysts with enhanced CO adsorption capacity and efficient H2O (steam) splitting activity offers a practical approach to catalyze the shift reaction at high, medium, and low temperatures tailored for different syngas technologies. Here, we report Co based catalyst (Co@BaNb2Ox) and Ru-based (Ru-Cs-MgCeAl2Ox) catalysts for high (or medium) water gas shift reaction. An equilibrium conversion was approached at low temperature (275 oC) at steam to carbon ratio of 4 for high temperature shift reaction for Co-based catalyst. Ru-based catalyst had shown similar performance but at high WHSVs.
Preliminary testing of Ru-based (Ru-MgO) catalyst for steam methane reforming reaction had shown promising results. Further improvements to enhance the catalytic activity by alkali/alkaline promotions will be evaluated.
Additional research work:
Designing the Co-free cathode materials for Li-ion batteries. There is an immediate requirement for the replacement of Co due the geographical issues and health hazard surrounding Co mining in Africa. Ni is an immediate alternative for Co in cathode materials for almost every electro and thermal catalytic reactions.
Work experience:
At Topsoe, worked as process engineer for syngas technologies. Prepared BEDP for Hydrogen, Ammonia and Methonol Technologies.
Proposal Engineer:
Prepared proposals for hydrogen technology with different capacities
Development Engineer:
Reactor and technology development for Methanol and GTL technologies.
My PhD research and work experience have been very interdisciplinary in nature. Having a strong background in basic design and engineering, with proposals, reactor design, and technology development for syngas-based technologies (covering hydrogen, ammonia, and methanol) at Topsoe and catalyst development for ammonia decomposition, WGS and SMR reactions during PhD had given in-depth knowledge of reactor development. Additionally, my master’s thesis on vapor-liquid equilibria for associating fluids under slit-pore confinement using Monte Carlo and molecular dynamics simulation at IIT Kanpur gave a different perspective about the reactant’s behavior on the catalyst surface. The catalyst synthesis along with several morphological characterizations enhanced understanding of material science. Furthermore, elective courses related to material science and electrochemical engineering have allowed me to develop cathode materials for lithium-ion batteries. Worked extensively on designing software equivalent to ASPEN HYSYS and HTRI along with molecular simulation software like Material Studio. With good amount of design and development experience, and research experience (catalyst and cathode material development and thermodynamics simulation) could be good fit for the jobs involving catalyst, reactor, and technology development.